The development of probes for fluorescence imaging is an area that is currently attracting considerable attention across a wide range of fields. Fluorescent probes are one of the cornerstones in the interdisciplinary fields of materials chemistry, biology and medicine. The understanding of complex systems is increasingly dependent on the ability to visualize and quantify signaling molecules with high spatial and temporal resolution. Great efforts have been made toward the development of new probes with high fluorescence efficiency in the red spectral region. So far, various materials including fluorescent proteins, small organic fluorophores, dye-doped beads or inorganic semiconductor quantum dots have been widely exploited for fluorescence imaging. However, the use of organic fluorophores and fluorescent proteins is hampered by inherent drawbacks such as poor photostability and blinking behavior. Dye-doped beads have a relatively large size and limited protection of the dye molecules, making these probes prone to leaching. Quantum dots show greater fluorescent quantum yields and greater tolerance to photobleaching compared to organic dyes. However, QDs are hydrophobic by nature, thereby they require layers of polymeric or inorganic material to make them compatible them with the aqueous environment. Moreover in the oxidative environment they tend to leak metal ions, inducing cytotoxicity. Thus, there is a need to overcome these deficiencies or difficulties.